It is known for a one-time-use camera to be used with a film cassette having a film spool inside the cassette that is windingly rotated to progressively wind a filmstrip into the cassette following each exposure and a light lock that is to be pivoted closed after the filmstrip is completely wound into the cassette following the last exposure. The light lock must be pivoted closed to prevent ambient light from entering the film cassette when the cassette is removed from the camera.
Commonly assigned U.S. Pat. No. 5,579,070 issued Nov. 26, 1996 discloses a one-time-use camera for use with the film cassette. The camera includes a single-piece closing unit having a film sensing portion that is spring-urged against the filmstrip as the filmstrip is progressively wound into the cassette and a closing portion in rotational engagement with the light lock. The film sensing portion determines that the filmstrip is completely wound into the cassette, and the closing portion then closes the light lock. When the filmstrip is completely wound into the cassette, the film sensing portion is free to be spring-urged because it is no longer restrained by the filmstrip. The spring-urging rotates the closing unit to simultaneously pivot the film sensing portion into a stop cavity and rotate the closing portion to partially close the light lock. Then, a hand tool must be manually engaged with the closing unit to further rotate the closing unit to rotate the closing unit to fully close the light lock. Since the film sensing portion is located in the stop cavity, it is then broken off the closing unit. When the film cassette is removed from the camera, the closing unit--absent the film sensing portion--is removed with the cassette.